Semiconductor cell array with high packing density

• US 6,005,271 A
• Filed: 11/05/1997
• Issued: 12/21/1999
• Est. Priority Date: 11/05/1997
• Status: Expired due to Term

• Current Assignee: Alpha & Omega Semiconductor, Ltd.
• Original Assignee: MagePower Semiconductor Corporation
• Inventors: Hshieh, Fwu-Iuan
• Primary Examiner(s): Saadat, Mahshid
• Assistant Examiner(s): Eckert, II, George C.
• Application Number:
  US08/964,775
• Time in Patent Office: 776 Days
• Field of Search: 257/331, 257/341, 257/401
• US Class Current: 257/341
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A MOSFET (Metal Oxide Semiconductor Field Effect Transistors) cell array formed on a semiconductor substrate includes a major surface formed with a plurality of MOSFET cells. Each semiconductor cell in the cell array is geometrically configured with a base portion and a plurality of protruding portions extending from the base portion. The base and protruding portions define a closed cell boundary enclosing each semiconductor cell. The closed cell boundary of each semiconductor cell is disposed on the major surface proximal to and in geometrical accord with the corresponding cell boundaries of other adjacent semiconductor cells in the cell array. As arranged, the cell boundary and thus the channel width of each cell is extended without any concomitant reduction in cell area.

Claims

1. A semiconductor cell array comprising:

a semiconductor substrate having a major surface; and

a plurality of semiconductor cells, each of said semiconductor cells being geometrically configured with a base portion and a plurality of protruding portions extending from said base portion such that said base and said protruding portions define a closed cell boundary enclosing each of said semiconductor cells;

wherein said plurality of semiconductor cells being formed on said major surface with said closed cell boundary of each of said semiconductor cells being disposed in geometrical accord with the corresponding cell boundaries of other adjacent semiconductor cells in said cell array, such that each of said protruding portions of each of said semiconductor cells being proximally extended into the space separated by the protruding portions of said other adjacent semiconductor cells on said major surface.

2. The semiconductor cell array as said forth in claim 1 wherein each of said semiconductor cells being geometrically configured with one base portion and four protruding portions extending from said base portion.

3. The semiconductor cell array as said forth in claim 2 wherein said closed cell boundary is cross-shaped.

4. The semiconductor cell array as said forth in claim 3 wherein each of said protruding portions includes a width and a length, and wherein said closed boundary is disposed at a predetermined separation from the corresponding cell boundaries of other adjacent semiconductor cells in said cell array, such that each of said cells being geometrically configured and disposed on said major surface with the sum of said width and said predetermined separation being equal to twice said length.

5. The semiconductor cell array as set forth in claim 1 wherein each of said semiconductor cells includes a source region and a cell contact region, each of said semiconductor cells is configured with said closed cell boundary surrounding said source region which in turn surrounds said cell contact region.

6. The semiconductor cell array as set forth in claim 1 wherein selected protruding portions of each of said semiconductor cells are geometrically connected with other selected protruding portions of other adjacent semiconductor cells of said cell array via connecting bridges.

7. The semiconductor cell array as set forth in claim 1 wherein each of said semiconductor cells is a trenched field-effect transistor.

8. The semiconductor cell array as set forth in claim 1 wherein each of said semiconductor cells is a planar field-effect transistor.

9. A semiconductor cell array comprising:

a semiconductor substrate having a major surface; and

a plurality of semiconductor cells formed on said major surface, each of said semiconductor cells being geometrically configured with a base portion and four protruding portions extending from said base portion such that said base and said protruding portions form a closed cross-shaped boundary enclosing each of said semiconductor cells, such that each of said protruding portions of each of said semiconductor cells being proximally extended into the space separated by the protruding portions of said other adjacent semiconductor cells on said major surface.

10. The semiconductor cell array as set forth in claim 9 wherein each of said semiconductor cells includes a source region and a cell contact region, each of said semiconductor cells is configured with said closed boundary surrounding said source region which surrounds said cell contact region.

11. The semiconductor cell array as said forth in claim 10 wherein each of said protruding portions includes a width and a length, said closed boundary is disposed at a predetermined separation from the corresponding cell boundaries of other adjacent semiconductor cells in said array, said plurality of semiconductor cells being formed on said major surface with said closed cell boundary of each of said semiconductor cells proximally disposed and in geometrical accord with the corresponding cell boundaries of other adjacent semiconductor cells of said cell array such that each of said semiconductor cells being geometrically configured and disposed on said major surface with the sum of said width and said predetermined separation being equal to twice said length.

12. The semiconductor cell array as set forth in claim 11 wherein selected protruding portions of each of said semiconductor cells are geometrically connected with other selected protruding portions of other adjacent semiconductor cells of said cell array.

13. The semiconductor cell array as set forth in claim 12 wherein each of said semiconductor cells is a trenched field-effect transistor.

14. The semiconductor cell array as set forth in claim 12 wherein each of said semiconductor cells is a planar field-effect transistor.

15. The semiconductor cell array as set forth in claim 11 wherein each of said semiconductor cells is a trenched field-effect transistor.

16. The semiconductor cell array as set forth in claim 11 wherein each of said semiconductor cells is a planar field-effect transistor.

17. A semiconductor cell array comprising:

a semiconductor substrate having a major surface; and

a plurality of semiconductor cells formed on said major surface, each of said semiconductor cells being geometrically configured with a base portion and four protruding portions extending from said base portion, such that said base and said protruding portions form a closed cross-shaped boundary enclosing each of said semiconductor cells;

wherein each of said protruding portions includes a length a and a width b, said closed boundary is disposed at a predetermined separation t from the corresponding cell boundaries of other adjacent cells in said cell array, said plurality of semiconductor cells being formed on said major surface with said closed cell boundary of each of said semiconductor cells proximally disposed and in geometrical accord with the corresponding cell boundaries of other adjacent semiconductor cells of said cell array on said major surface in accordance with the mathematical relationship;

2a=b+t.

18. The semiconductor cell array as set forth in claim 17 wherein each of said semiconductor cells is a trenched field-effect transistor.

19. The semiconductor cell array as set forth in claim 17 wherein each of said semiconductor cells is a planar field-effect transistor.